Building Broadband Networks by Marlyn Kemper Littman

Chapter 4: Networks

4.9 Technical Fundamentals As with its Ethernet and predecessors, Gigabit Ethernet technology works in wireless and wireline environments. A multifunctional communications technology, Gigabit Ethernet significantly expands available bandwidth for enabling interactive, high-performance multimedia applications. In comparison to Fast Ethernet, Gigabit Ethernet increases the rates at which data are transmitted by a factor of ten. In contrast to its predecessor, Gigabit Ethernet employs the physical signaling scheme described in the Fibre Channel specification for enabling packet transmission.

4.9.1 Gigabit Ethernet Functions Gigabit Ethernet networks utilize the underlying infrastructure established with Ethernet and Fast Ethernet specifications. As a consequence, Gigabit Ethernet enables a straightforward migration path to higher performance levels without disrupting in-place networking operations. Generally viewed as an extension of Ethernet and Fast Ethernet, Gigabit Ethernet technology ensures seamless interworking with Ethernet and Fast Ethernet services and operations. Gigabit Ethernet also employs the same protocols, transmission schemes, frame size, frame format, flow control procedures, and access methods as Ethernet and Fast Ethernet. Therefore, the need for complex emulation and translation techniques to support migration from Ethernet and Fast Ethernet implementations to Gigabit Ethernet solutions is eliminated.

4.9.2 Gigabit Ethernet Architecture Gigabit specifications support half-duplex and full-duplex operations; gigabit transmissions over two strands of optical fiber or two pairs of shielded twisted copper wires; and encoding schemes defined by the ANSI Fibre Channel standard. The network topology for Gigabit Ethernet conforms to the conventional specifications for Ethernet and Fast Ethernet. In conjunction with Ethernet and Fast Ethernet, Gigabit Ethernet employs Layer 1 or the Physical Layer and the Media Access Control (MAC) Sublayer of Layer 2 or the Data-Link Layer for information transport. Additionally, Gigabit Ethernet works in conjunction with upper layer protocols such as IP (Internet Protocol) and TCP (Transmission Control Protocol). In terms of the OSI Reference Model, IP and TCP utilize the Transport Layer or Layer 4 and the Network Layer or Layer 3 for enabling communications services between applications.

4.9.3 Gigabit Ethernet Operations Gigabit Ethernet implementation is basically a replication of deployment procedures associated with its predecessors. Moreover, in-place Ethernet and Fast Ethernet management systems and equipment function in concert with Gigabit Ethernet management systems, services, and applications, thereby enabling cost-effective migration to advanced Gigabit Ethernet solutions. Early Gigabit Ethernet implementations employed optical fiber for supporting full-duplex transmissions and facilitating building-to-building LAN interconnections. As evidenced by the ratification of the Gigabit Ethernet over copper cabling standard by the IEEE, Gigabit Ethernet also works effectively with Unshielded Twisted Pair (UTP) in delivering services to the desktop. As with previous Ethernet generations, Gigabit Ethernet is scalable and extendible, augments functions of in-place networks, and enables a broad array of applications. In the LAN arena, Gigabit Ethernet supports links between servers and switches and interconnects clusters of servers, server farms, and network segments. In addition, Gigabit Ethernet provisions high-speed connections between buildings and supports transmissions ranging from 10 Mbps to 1000 Mbps or 1 Gbps and higher rates. Moreover, Gigabit Ethernet installations are less costly than ATM in terms of implementation, operations, administration, and maintenance. It is important to note that Gigabit Ethernet and its predecessors are subject to distance and signal constraints. Transmission impairments result in attenuation or signal power loss, near-end crosstalk (NEXT), and latencies in signal transport.

4.9.4 IEEE 802.3z or Fiber Optic Gigabit Ethernet Implementations The IEEE 802.3z specification for extending Gigabit Ethernet functions into the optical fiber environment was ratified in 1998. Endorsed by the IEEE 802.3z Gigabit Ethernet Task Force, the Gigabit , and the IEEE Standards Committee, the IEEE 802.3z standard defines Ethernet operations at rates of 1000 Mbps or 1 Gbps for half-duplex transmissions and Ethernet operations at 2000 Mbps or 2 Gbps for full-duplex transmissions. The Gigabit Ethernet IEEE 802.3z standard also clarifies capabilities of that operate in conjunction with single-mode and multimode optical fiber plants and supports ongoing utilization of in-place optical fiber links that interconnect multiple buildings in campus LANs. The role of optical components such as optical lasers in transporting data-, voice-, and video-over-optical fiber is also indicated.

4.9.4.1 Gigabit Media Independent Interface (GMII) The IEEE 802.3z specification also describes Gigabit Media Independent Interface (GMII) services. The GMII enables interconnectivity of MAC Sublayer protocol devices with the Physical Layer or Layer 1 of the OSI Reference Model. Furthermore, the GMII supports half-duplex and full-duplex transmissions, multivendor interoperability, and backward compatibility with Ethernet and Fast Ethernet installations. In addition, the GMII enables virtual independent pathways or channels for data transmission and reception.

4. Solutions Based on the work of the IEEE 802.3z Gigabit Ethernet Task Force and the Gigabit Ethernet Alliance and ratified by the IEEE, the Gigabit Ethernet standard defines network interfaces, repeater operations, topologies, and capabilities of 1000BASE-SX and 1000BASE-LX configurations. The IEEE 802.3z Gigabit Ethernet Task Force and the Gigabit Ethernet Alliance also clarify features and functions of 1000BASE-LH and 1000BASE-CX networks.

4.10.1 1000BASE-SX Based on the Fibre Channel signaling standard, 1000BASE-SX describes Gigabit Ethernet short wavelength solutions. In supporting full-duplex mode transmissions, each 1000BASE-SX network segment enables transmission via multimode optical fiber at distances that extend to 275 meters. In addition, each 1000BASE-SX network segment supports full-duplex information transport over single-mode optical fiber at distances that extend to 550 meters.

4.10.2 1000BASE-LX 1000BASE-LX describes long wavelength Gigabit Ethernet solutions. With full-duplex mode operations, each 1000BASE-LX network segment facilitates transmissions via single-mode optical fiber at distances that reach 5000 meters. In enabling full-duplex operations over multimode optical fiber, each 1000BASE-LX network segment enables voice, video, and data transport at distances that extend to 550 meters.

4.10.2.1 Differential Mode Delay (DMD) The IEEE 802.3z Gigabit Ethernet Task Force also developed a solution for reducing the adverse impact of Differential Mode Delay (DMD), a condition that generates jitter in LED (Light Emitting Diode) installations supporting transmissions via multimode optical fiber. According to this Task Force, the utilization of conditioners with 1000BASE-LX and 1000BASE-SX configurations and dispersal of light pulses evenly through every lightpath or channel in each network segment resolves DMD transmission disruptions.

4.10.3 1000BASE-LH Supported by the IEEE 802.3z Gigabit Ethernet Task Force and the Gigabit Ethernet Alliance, 1000BASE-LH defines long-haul fiber optic Gigabit Ethernet Metropolitan Area Network (MAN) solutions that operate in multivendor urban environments.

4.10.4 1000BASE-CX Developed by the IEEE 802.3z Gigabit Ethernet Task Force and the Gigabit Ethernet Alliance, 1000BASE-CX refers to Gigabit Ethernet transmission over Category 5 Unshielded Twisted Pair (UTP). Each 1000BASE-CX network segment enables full-duplex operations at distances that extend to 25 meters.

4.10.5 IEEE 802.3ab or 1000BASE-T The IEEE ratified the IEEE 802.3ab standard, also known as 1000BASE-T, in 1999. This standard is based on research efforts sponsored by the Gigabit Ethernet Alliance. To verify 1000BASE-T capabilities, tests benchmarking the performance of Gigabit Ethernet over copper wiring were conducted by Gigabit Ethernet Alliance participants, including Alteon Web System, Extreme Networks, 3Com, and Sun Microsystems, at the Silicon Valley Networking Lab (SVNL). These tests evaluated Gigabit Ethernet performance in seamlessly enabling interoperability, full-motion video, groupware applications, and remote file transfers over Category 5 UTP (Unshielded Twisted Pair). Findings contributed to IEEE endorsement of the 1000BASE-T Giga-bit Ethernet-over- copper wire specification. 1000BASE-T solutions utilize four pairs of Category 5 UTP copper wires for enabling transmissions up to 100 meters over a single network segment. Each copper pair supports throughput at 250 Mbps for enabling a total transmission of 1000 Mbps or 1 Gbps in half-duplex mode and 2000 Mbps or 2 Gbps in full-duplex mode. Because 1000BASE-T installations work in conjunction with the installed Category 5 wireline infrastructure, the need to rewire ceilings, walls, or raised floors is eliminated. 1000BASE-T is compatible with Ethernet and Fast Ethernet technologies and works in concert with 56 Kbps (Kilobits per second) modems. A high-performance networking solution, 1000BASE-T also enables innovative desktop applications and high-speed server connectivity. Techniques employed by 1000BASE-T for eliminating signal degradation resulting from signal attenuation, echo, impulse noise, and near-end crosstalk associated with UTP transmission include line coding, pulse shaping, and forward error correction (FEC). Specifications for enabling 1000BASE-T implementations to support traffic over Category 6 and Category 7 cabling systems are in development.

4.10.6 1000BASE-2 The Gigabit Ethernet Alliance endorses the utilization of Category 5e (Enhanced Category 5) cabling for 1000BASE-2 installations.

4.11 Gigabit Ethernet Protocols Gigabit Ethernet provisions higher level services than its predecessors by leveraging capabilities of technologies, standards, and protocols such as the Resource Reservation Protocol (RSVP), the Real- Time Transit Protocol (RTP), the Real-Time Control Protocol (RTCP), and the Real-Time Streaming Protocol (RTSP). In addition, Gigabit Ethernet also supports operations in concert with the IEEE 802.1p and the IEEE 802.1Q specifications. To enable multimedia transmission, Gigabit Ethernet reserves bandwidth for voice, video, and data transmission; assigns priority CoS (Class of Service) tags to packets for conveying CoS levels to internetworking devices; and provisions priority queues to transport real-time data, voice, and video traffic over IP.

4.11.1 Resource Reservation Protocol (RSVP) Also called the Resource Reservation Setup Protocol, the RSVP (Resource Reservation Protocol) dynamically allocates bandwidth to network applications in conventional packet networks. With RSVP implementation, multimedia applications running on Gigabit Ethernet implementations can request a specified CoS (Class of Service) assurance. Internetworking devices such as routers and switches respond to an RSVP request by creating a virtual connection through the network for enabling the specified CoS assurance. Vendors such as 3Com and employ RSVP services to facilitate dependable and reliable delivery of multimedia network applications and support distributed broadband connections. In addition to providing CoS assurances, the Resource Reservation Protocol supports QoS (Quality of Service) functions such as guaranteed bandwidth reservation for enabling real-time multimedia transmissions via LANs and VLANs (Virtual LANs). RSVP facilitates operations at Layer 3 or the Network Layer of the OSI Reference Model.

4.11.2 Real-Time Transit Protocol (RTP) Gigabit Ethernet also works in concert with the Real-Time Transit Protocol (RTP). RTP is a transport protocol that supports delivery of continuous media such as real-time audio, video, or simulation data over the Internet. RTP supports time-stamping, sequence numbering, and payload identification for ensuring dependable packet delivery in real-time. In addition, RTP provides a framework for end-to-end network delivery of IP multicast traffic, works in concert with RSVP operations, and enables resource reservation for transporting bandwidth-intensive applications. RTP facilitates Gigabit Ethernet applications that include Web-based videoconferences, voice-over- IP (VoIP), and real-time transport of multimedia on-demand. In ATM networks, RTP provisions QoS guarantees. 4.11.3 Real-Time Control Protocol (RTCP) The Real-Time Control Protocol (RTCP) works in conjunction with the RTP to provide data on distribution faults that support network management operations. By controlling transmission intervals and preventing IP multicasts from inundating network resources, RTCP enables extendible and scalable RTP operations.

4.11.4 Real-Time Streaming Protocol (RTSP) The Real-Time Streaming Protocol (RTSP) supports streaming voice, video, and data for enabling point-to-multipoint IP multicast distributions. Streaming operations involve dividing voice, video, and data into numerous packets for network transmission and reconstituting the packets at the destination address.

4.12 Gigabit Ethernet Class of Service (COS) Assurances Gigabit Ethernet provisions Class of Service, also referred to as QoS assurances, rather than QoS guarantees. In provisioning higher-level services, Gigabit Ethernet leverages capabilities of technologies and protocols such as MPLA (MultiProtocol ) and MPLS (MultiProtocol Label Switching) to support network extendibility, scalability, and reliable packet transmission.

4.12.1 Multiprotocol Link Aggregation (MPLA) The IETF MultiProtocol Link Aggregation (MPLA) Working Group develops MPLA technology to support the integration of multiple physical connections into one virtual connection for enabling fast and dependable information transport in point-to-point and point-to-multipoint implementations. MPLA technology optimizes network performance and enables cost-effective and scalable operations for accommodating current and next-generation transmission requirements for applications such as videoconferencing, telecollaborative engineering, and interactive VR (Virtual Reality) simulations.

4.12.2 Multiprotocol Label Switching (MPLS) The IETF (Internet Engineering Task Force) MultiProtocol Label Switching (MPLS) Working Group establishes criteria for utilization of an MPLS solution. Based on a label-switching technology, MPLS supports the attachment of a label to every network packet that establishes the packet path through the network. Labels such as CoS and QoS identify packets that warrant priority services. In addition, the MPLS solution defines procedures for distributing IP multicasts and label packets to optimize network performance. Gigabit Ethernet supports MPLS functions. In addition, Packet-over-SONET/SDH (POS), Frame Relay, and ATM also benefit from MPLS operations.

4.13 Gigbit Ethernet Standards Organizations and Activities

4.13.2 Gigabit Ethernet Alliance The Gigabit Ethernet Alliance is a multivendor consortium that supports implementation of affordable and interoperable Gigabit Ethernet solutions. This group encourages the seamless migration from in-place Ethernet and Fast Ethernet installations to Gigabit Ethernet deployments in response to the demand for increased network bandwidth. The Gigabit Ethernet Alliance also endorses the continued use of the conventional format and traditional network management guidelines. In addition, the Gigabit Ethernet Alliance supports backward compatibility of Gigabit Ethernet installations with on-site Ethernet and Fast Ethernet networks for leveraging infrastructure investments. The Gigabit Ethernet Alliance also conducts interoperability tests for verifying capabilities of Gigabit Ethernet products. Founding members of the Gigabit Ethernet Alliance include Cisco Systems, Sun Microsystems, VLSI Technology, Compaq, LSI Logic, Intel, and UB Networks. The Gigabit Ethernet Alliance is now part of the 10 GEA.

4.13.3 Gigabit Ethernet Consortium Formed in 1997, the Gigabit Ethernet Consortium evaluates Gigabit Ethernet product quality and the performance, reliability, and availability of Gigabit Ethernet implementations in research and actual environments. The Gigabit Ethernet Consortium employs a series of test suites for ensuring standards compliance of IEEE 802.3z devices such as switches, routers, and transceivers in research trials conducted at the University of New Hampshire InterOperability Lab (IOL). As with the Fast Ethernet Consortium, the Gigabit Ethernet Consortium is a vendor coalition.

4.14 Ethernet VLANS (Virtual LANs)

4.14.1 VLAN Capabilities Ethernet, Fast Ethernet, and Gigabit Ethernet switches enhance network performance and security and facilitate access to bandwidth-intensive multimedia applications. These devices also enable network segmentation to support development and implementation of VLANs (Virtual Local Area Networks). An Ethernet, Fast Ethernet, or Gigabit Ethernet VLAN refers to a logical grouping of network stations or nodes that function as if they are connected to a single shared medium regardless of their physical network locations. Switches are sophisticated devices that foster interconnections of network stations and resources situated on physically different network segments into logical VLAN configurations. Ethernet, Fast Ethernet, and Gigabit Ethernet VLANs are typically deployed for enabling interactive communications among individuals participating in common workgroup activities. Generally found in larger enterprises such as universities and corporations, VLANs enable constituent workgroups to communicate with each other, share multimedia resources and available bandwidth, and jointly participate in online activities.

4.14.2 VLAN Operations An Ethernet, Fast Ethernet, or Gigabit Ethernet VLAN is a flexible configuration that is easy to manage, administer, and maintain. Network administrators readily identify network stations in trouble in VLAN implementations, thereby eliminating the need to shut down the network. Because network stations can be quickly added to and deleted from VLAN configurations, the need to rewire the on-site installation for enabling diverse workgroup tele-applications is eliminated. Inasmuch as network routers move traffic between an enterprisewide network for supporting intra-workgroup VLAN capabilities, information flow is predictable and on-demand bandwidth can be made available for multimedia applications. In addition, network servers that are configured to provision applications for multiple VLAN workgroups generally can optimize network response time by eliminating excessive router traffic and reducing network bottlenecks. 4.14.3 IEEE 802.1Q VLAN Specification VLAN implementations typically conform to requirements described in the IEEE 802.1Q specification. Designed for Ethernet, Fast Ethernet, and Gigabit Ethernet VLANs, the IEEE 802.1Q specification defines VLAN attributes and capabilities and indicates approaches for resource sharing and information exchange in VLAN configurations. Moreover, the IEEE 802.1Q specification describes VLAN architecture, clarifies network administrative functions, and streamlines the VLAN implementation process. In addition, this specification provides a foundation for enabling the interoperability of VLAN installations in multivendor environments.

4.14.3.1 IP Multicasts Protocols defined by the IEEE 802.1Q specification support IP multicasts in Ethernet, Fast Ethernet, and Gigabit Ethernet VLAN configurations. IP multicasts enable multimedia distribution via the Internet. Traditional unicast approaches for transmitting voice, video, and data via point-to-point links are no longer effective in provisioning multimedia delivery. As a consequence, the Multicast Backbone (MBone) provisions point-to-multipoint and multipoint-to-multipoint multicast distributions to specified groups of recipients.

4.14.3.2 Multicast Protocols In Ethernet, Fast Ethernet, and Gigabit Ethernet VLANs, the Generic Attribute Registration Protocol (GARP), the GARP VLAN Registration Protocol (GVRP), and the GARP Multicast Registration Protocol (GMRP) support dynamic creation of multicast groups. Multicast routing protocols such as the Distance Vector Multicast Routing Protocol (DVMRP) foster development of multicast delivery paths for transmission of multicast packets through the network to specified multicast groups. The GARP Multicast Registration Protocol (GMRP) and the Internet Group Management Protocol (IGMP) identify problems with multicast transmission and facilitate implementation of procedures for multicast delivery that do not compromise network operations.

4.15 IEEE 802.1p Specification

4.15.1 IEEE 802.1p Capabilities Approved in 1998 by the IEEE 802.1p Working Group as part of the IEEE 802.1 standard for bridges, the IEEE 802.1p specification supports development of next-generation converged Ethernet configurations. These configurations deliver scalable applications with differentiated service requirements such as desktop videoconferencing, televideo training, and voice-over-IP (VoIP). The IEEE 802.1p specification optimizes network throughput, transmission efficiencies, and network response times. Moreover, the IEEE 802.1p specification enables seamless operations across multivendor environments, equipment monitoring, and network administrative activities. The IEEE 802.1p specification also fosters establishment of multicast groups to reduce inundation of network resources when IP multicasts are used for multimedia distribution. In addition, this specification supports priority queuing mechanisms for handling high-priority traffic.

4.15.2 IEEE 802.1p and IEEE 802.1Q Operations As with the IEEE 802.1Q standard, the IEEE 802.1p specification defines the purpose of the Generic Attribute Registration Protocol (GARP). GARP enables specific applications and protocols such as the GARP Multicast Registration Protocol (GMRP) and the GARP VLAN Registration Protocol (GVRP). With GMRP, a network station requests VLAN admission as opposed to requesting admission to a multicast domain. In parallel with IEEE 802.1Q operations, IEEE 802.1p GMRP service also delivers IP multicasts by using GARP for registering multicast membership. GMRP works in concert with IP multicast protocols operating at the Network Layer or Layer 3 of the OSI Reference Model in order to provide efficient multicast operations, administrative control of multimedia traffic, bandwidth conservation, and management of multicast addresses.

4.19 Gigabit Ethernet Implementation Considerations Fast Ethernet and Gigabit Ethernet share common network components and support joint topologies and network architectures. These technologies also facilitate connectivity to legacy networks and provide a scalable approach for achieving very high data rates. The transition to higher-speed Ethernet networks can be readily accomplished without large-scale reinvestment. Fast Ethernet and Gigabit Ethernet networks provide high-capacity advanced network services for new classes of applications that cannot function effectively in the current network infrastructure. The appeal of Fast Ethernet and Gigabit Ethernet stems from their structural and functional compatibility with each other and with conventional Ethernet solutions. In parallel with Ethernet and Fast Ethernet, Gigabit Ethernet can be implemented in incremental phases, employs CSMA/CD to resolve contention for the shared medium, and supports operations in full-duplex and half-duplex modes. In full-duplex operations, Gigabit Ethernet enables rates at 2 Gbps via point-to-point and switch-to-server links. Gigabit Ethernet also employs frame flow control as a CSMA/CD enhancement for enabling switch-to-node and switch-to-switch connections. In instances of shared port connections, Gigabit Ethernet supports transmissions in half-duplex mode at rates reaching 1 Gbps and transmissions in full-duplex mode at rates reaching 2 Gbps. Typically, Gigabit Ethernet is deployed in backbone network environments that require increased bandwidth between routers, centralized hubs, repeaters, servers, and switches. As with Fast Ethernet, Gigabit Ethernet enables advanced applications and services in fields that include distance learning, telemedicine, E-government, and E-commerce. Gigabit Ethernet also works in conjunction with established applications, platforms, operating systems, protocols, and technologies. In addition, Gigabit Ethernet interoperates with Ethernet and Fast Ethernet technologies and on-site equipment supporting earlier Ethernet deployments. As a consequence, migration to a Gigabit Ethernet installation is a straightforward process. Gigabit Ethernet is a robust multivendor solution that can be built with Gigabit Ethernet devices such as adapters and 100/1000 Mbps dual-mode Gigabit Ethernet switches from diverse manufacturers. Gigabit Ethernet is distinguished from its Ethernet predecessors by its support of higher bandwidths, faster response times, and substantial improvements in backbone and server performance. A versatile and flexible technology, Gigabit Ethernet supports Layer 3 or Network Layer switching and routing operations and employs upper-layer protocols for enabling IP multicasts and CoS assurances. In addition, Gigabit Ethernet facilitates seamless network extendibility and scalability at those enterprises with plans to integrate additional servers and Web caches into the network infrastructure for supporting data-intensive applications such as bulk file transfers and on-demand publishing via in-place configurations. Nonetheless, there are challenges associated with effective Gigabit Ethernet deployment. Gigabit Ethernet implementations require new tools and components for network monitoring, troubleshooting, and management operations. In addition, Gigabit Ethernet installations require a flexible architecture that supports switched data streams, throughput at gigabit rates, and access to intranets, extranets, and next-generation applications and services. Gigabit switching and interface products are necessary to provision a smooth and scalable migration path from current Ethernet and Fast Ethernet configurations to Gigabit Ethernet network installations. Moreover, approaches for enabling the co-existence and interoperations of Gigabit Ethernet and ATM services must also be defined. Gigabit Ethernet operations are subject to functional constraints. Gigabit Ethernet standards for transporting traffic over copper cabling are relatively recent and not fully tested in actual networking environments. Strategies for transporting multimedia via Gigabit Ethernet links are still in development. Further, Gigabit Ethernet is not currently capable of fully guaranteeing congestion control and enabling automatic rerouting of network traffic in case of network gridlock. Despite expectations associated with Gigabit Ethernet implementations, early field trials of Gigabit Ethernet operations indicate the installed base of workstations and servers may not be able to support gigabit links and take advantage of higher throughput. As a consequence, although Gigabit Ethernet is perceived as yet another Ethernet incarnation, its implementation involves establishing staff responsibilities for Gigabit Ethernet services and a budget for acquisition of standards- compliant Gigabit Ethernet switches, repeaters, hubs, and routers to support substantial improvements in network operations and functions. New devices such as buffered distributors and full-duplex repeaters for enabling interconnectivity between two or more Gigabit Ethernet configurations operating at 1 Gbps and faster rates are in development. In the absence of auxiliary equipment such as buffered distributors, Gigabit Ethernet is limited in provisioning CoS assurances for multimedia traffic and sustaining error-free multimedia transport. The provision of sustained support and seamless interoperability is critical to the acceptance and deployment of Gigabit Ethernet technology. Future Gigabit Ethernet implementations are expected to routinely interwork with Ethernet and Fast Ethernet switches featuring speed translation capabilities for enabling interoperable services. In addition, approaches for provisioning full-scale interoperability between Gigabit Ethernet and ATM technologies are also in development. A Gigabit Ethernet solution enables an enterprise to leverage its investment in the in-place Ethernet and Fast Ethernet infrastructure while boosting network performance and realizing the benefits of high-speed networking. With Gigabit Ethernet, research centers, educational institutions, government agencies, and hospitals can accommodate accelerating bandwidth requirements for enabling such network applications as videoconferencing, data warehousing, medical imaging, and scientific simulations, and fostering dependable access to intranets, extranets, and Web resources. As a consequence of its capabilities in interworking with diverse narrowband and broadband technical solutions, Gigabit Ethernet technology is regarded as a key enabler of next-generation network implementations. The popularity of Gigabit Ethernet solutions is reflected in the wide range of initiatives sponsored by healthcare centers, universities, corporations, and government organizations. Representative initiatives are examined later in this chapter.

4.20 10 Gigabit Ethernet

4.20.1 10 Gigabit Ethernet Technical Fundamentals The remarkable growth of Internet traffic and the widespread popularity of Ethernet technologies contribute to development and implementation of the 10 Gigabit Ethernet specification by the IEEE 802.3 High-Speed Study Group and the formation of the IEEE 802.3ae Task Force for coordinating standards activities in the 10 Gigabit Ethernet domain.

4.20.2 10 Gigabit Ethernet Operations Gigabit Ethernet technology is a logical extension to the Ethernet family of standards and retains the IEEE 802.3 frame format and packet size of its predecessors. Moreover, 10 Gigabit Ethernet solutions are designed to work in concert with Ethernet, Fast Ethernet, and Gigabit Ethernet technologies, architectures, and protocols. 10 Gigabit Ethernet networks support operations at Layer 1 or the Physical Layer and Layer 2 or the Data-Link Layer of the OSI Reference Model. By working in conjunction with the IEEE 802.3 MAC (Media Access Control) protocol, 10 Gigabit Ethernet enables full-duplex operations and utilizes equipment already employed for Ethernet, Fast Ethernet, and Gigabit Ethernet networks. In addition, by conforming to IEEE 802.3 protocols, 10 Gigabit Ethernet ensures operational compatibility with the installed base of Ethernet networks. In parallel with the three , 10 Gigabit Ethernet enables upper layer functions and provisions QoS assurances. 10 Gigabit Ethernet applications include IP telephony, video-on- demand (VOD), Web caching, server load balancing, and security and policy enforcement. 10 Gigabit Ethernet technology also operates with IETF (Internet Engineering Task Force) protocols such as MPLS (MultiProtocol Label Switching) and Simple Network Management Protocol (SNMP). Moreover, the Management Information Base (MIB) for 10 Gigabit Ethernet works in concert with the IEEE 802.3 MIBs (Management Information Bases) for Ethernet, Fast Ethernet, and Gigabit Ethernet installations. Additionally, 10 Gigabit Ethernet specifications support Ethernet, Fast Ethernet, and Gigabit Ethernet flow control procedures. However, in contrast to its predecessors, 10 Gigabit Ethernet is not expected to support CSMA/CD operations at half-duplex mode. In the LAN arena, 10 Gigabit Ethernet fosters high-speed interconnectivity between large-scale switches and bandwidth-intensive backbone networks, and supports seamless high-speed Internet, intranet, and extranet connections. In addition to provisioning LAN services, 10 Gigabit Ethernet supports operations performed in metropolitan and wider area networks. Gigabit Ethernet technology also enables significantly higher bandwidth capabilities than its predecessors for supporting current and next-generation voice, video, and data applications.

4.21 10 Gigabit Ethernet Standards Organizations and Activities

4.21.1 10 Gigabit Ethernet Alliance (10GEA) The 10 Gigabit Ethernet Alliance (10GEA) is an industry forum that supports widescale implementation of the 10 Gigabit Ethernet specification in LANs, MANs, and WANs and works with the IEEE 802.3ae Task Force to facilitate 10 Gigabit Ethernet standards development. In addition, the 10GEA promotes implementation of 10 Gigabit Ethernet solutions that work in concert with SONET/SDH (Synchronous Optical Network and Synchronous Digital Hierarchy), WDM (Wavelength Division Multiplexing), and DWDM (Dense WDM) technologies. Gigabit Ethernet Alliance members include Cisco, 3Com, Extreme Networks, Sun Microsystems, Intel, Nortel Networks, Ascend Communications, and Lucent Technologies. In addition, Apple Computer, 3M, Hewlett Packard, and Compaq Computer participate in the 10GEA as well. 4.21.2 IEEE P802.3a 10 Gigabit Ethernet Task Force Following approval by the IEEE 802.3 Higher Speed Study Group, 10 Gigabit Ethernet specifications were sent to the IEEE Standards Board. In 2000, this Board authorized moving forward with10 Gigabit Ethernet specifications within the IEEE P802.3ae 10 Gigabit Ethernet Task Force. The IEEE P802.3ae 10 Gigabit Ethernet Task Force supports development of 10 Gigabit Ethernet protocols that function in all-optical LAN, MAN, and WAN networking environments; clarifies guidelines for maintaining the Ethernet, Fast Ethernet, and Gigabit Ethernet frame size and frame format; and supports full-duplex 10 Gigabit Ethernet operations. This Task Force also facilitates development of Physical Layer or Layer 1 specifications for enabling 10 Gigabit Ethernet transmissions over multimode optical fiber at distances between 100 meters and 300 meters and single-mode optical fiber at distances of 2,000, 10,000, and 40,000 meters or 2, 10, and 40 kilometers.

4.21.3 IEEE 802.ah Ethernet First Mile Task Force In 2001, the IEEE 802.ah Ethernet in the First Mile Task (EFM) Force began work on development of a wireline 10 Mbps Ethernet local loop standard that provisions communications services over the first mile from the customer premise to the local telephone exchange. This Task Force clarifies network operations, management services, and architectures for first mile solutions. In addition, specifications to support 10 Mbps transmissions via point-to-point links over twisted copper pair wiring at distances that extend to 750 meters are in development. Moreover, standards for enabling 1000 Mbps or 1 Gbps transmissions via point-to-point and point-to-multipoint connections via optical fiber connections over distances that extend to 10,000 meters or 10 kilometers are under consideration.

4.22 10 Gigabit Ethernet Solutions Gigabit Ethernet technology supports interconnectivity between geographically distributed local networks; enables integrated LAN, MAN, and WAN implementations; and provisions affordable fast access to bandwidth-intensive multimedia applications over single-mode and multimode optical fiber. 10 Gigabit Ethernet services are carried directly over SONET/SDH, WDM, and DWDM infrastructures. For example, 10 Gigabit Ethernet-over-DWDM supports multimedia transmissions via a 50-micron multimode optical fiber core at distances that extend to 65 meters. With a 62.5- micron multimode optical fiber core, each 10 Gigabit Ethernet-over-DWDM network segment enables transmissions at a distance that extends to 300 meters. With a 9.0-micron single-mode optical fiber core, each 10 Gigabit Ethernet-over-DWDM network segment supports multimedia transport over distances extending from 10 kilometers to 40 kilometers.

4.22.1 10 Gigabit Optical Ethernet in Action Accelerating demand for fast Internet access and higher bandwidth services contributes to the development of optical Ethernet solutions in the vendor marketplace that are designed to work in conjunction with SONET/SDH, WDM, and DWDM technologies. Network configurations based on optical Ethernet solutions are scalable, extendible, and reliable, and support multigigabit interactive video, voice, and data applications. Implementation of 10 Gigabit Ethernet-over-DWDM installations in a metropolitan area network (MAN or metro) configuration enables service providers to support end-to-end IP information transport, use ubiquitous Ethernet interfaces, and extend the reach of VLANs across metropolitan and long-haul networks. 10 Gigabit Ethernet-over-DWDM implementations dependably deliver next-generation Ethernet services to multiple sites. By eliminating the relatively time-consuming process of electronic-to-optical and optical-to-electronic conversion and encapsulating Ethernet frames into other packet formats, 10 Gigabit Ethernet-over-DWDM installations streamline network operations.

4.32 Summary Ethernet, Fast Ethernet, Gigabit Ethernet, and 10 Gigabit Ethernet technologies enable the implementation of seamless integrated networks comprised of heterogeneous computing equipment and resources. The four Ethernets are distinguished by their support of reliable high-speed, volume- intensive transmissions in DANs, LANs, MANs, and WANs. This chapter explores capabilities of the four Ethernets in enabling reliable network performance in tele-education, telemedicine, and E- government applications and initiatives. Recent innovations in home networking are introduced. The role of the Ethernet suite of technologies in enabling home phoneline networks is described. Ethernet is among the world's most pervasive, popular, and ubiquitous technologies. The four Ethernets provision frameworks for flexible network solutions that are scalable and interoperable with a diverse array of network technologies, protocols, and architectures, including ATM, SONET/SDH, Frame Relay, FDDI, Fibre Channel, WDM, and DWDM solutions. Ethernet networks employ CSMA/CD, utilize a specified frame format, enable dependable half-duplex and/or full-duplex transmission, provision network management procedures and security mechanisms, and foster interconnectivity to wireline and wireless networks through compliance with specifications endorsed by the IEEE. Factors contributing to the accelerating numbers of Gigabit Ethernet implementations in telemedicine, E-government, and tele-education reflect Gigabit Ethernet's compatibility with previously established Ethernet and Fast Ethernet solutions and the need for faster networks to accommodate bandwidth demands of complex applications. Gigabit Ethernet is further distinguished by its self-healing architecture, support of VLANs for creating logical workgroups across the network, and capabilities in provisioning traffic prioritization for CoS assurances. Advanced protocols and switching technologies that support interoperability and interworking contribute to the convergence of Gigabit Ethernet and ATM networks and the emergence of 10 Gigabit Ethernet. 10 Gigabit Ethernet optical solutions enable robust networking implementations that extend from the network core to the desktop and work in concert with WDM and DWDM technologies. (See Figure 4.5.) Figure 4.5: A link between a long-haul DWDM (Dense Wavelength Division Multiplexing) switch and a Gigabit Ethernet connection for enabling optical information transport via a 10 Gigabit Ethernet implementation. Moreover, 10 Gigabit Ethernet optical configurations ensure consistent information throughput; support dependable voice, video, and data delivery; and provision bandwidth allocations to accommodate multiservice networking requirements. An understanding of distinctive features and functions of Ethernet, Fast Ethernet, Gigabit Ethernet, and 10 Gigabit Ethernet configurations is critical for enabling seamless and secure information transport and optimizing capabilities of tele- education, telemedicine, and E-government solutions.